1. Field
Example embodiments relate to a retainer ring, a polishing head, and a chemical mechanical polishing apparatus. For example, example embodiments relate to a retainer ring having a thermoelectric element and a polishing head and a chemical mechanical polishing apparatus, having the retainer ring.
2. Description of the Conventional Art
Chemical mechanical polishing (CMP) is a semiconductor manufacturing processes that may use a CMP apparatus having a polishing pad to polish a wafer. A chemical solution including a slurry may be used in a manner such that a chemical reaction is induced on a wafer, and mechanical force produced by the polishing pad may be transmitted to the wafer so as to planarize the surface of the wafer.
A CMP apparatus may include a platen, a polishing pad, and/or a polishing head, which may be composed of a retainer ring and a wafer carrier. When polishing the wafer surface by rotating the polishing head, the temperature may rise due to friction between the polishing pad and the retainer ring, friction between the retainer ring and the wafer, and/or friction between the wafer and the polishing pad. The increase in temperature may lower the yield of the CMP process. For example, erosion and dishing may occur to a greater extent at the edge of the wafer than at the center of the wafer. Erosion is a phenomenon in which a portion of a spacer on a relatively fine pattern is concavely removed during the polishing process. Dishing is a phenomenon in which a top portion of a layer deposited in a trench becomes concave, like a dish, during the polishing process.
In the conventional art, a cooling device may be arranged in a platen to lower the heat during a CMP process. However, because the polishing pad is formed of polyurethane having a low thermal conductivity, it may be difficult to effectively reduce the heat.